This invention relates to processing whole blood into platelet-rich plasma and, more particularly, to improvements in blood processing systems for generating platelet-rich plasma from autologous blood.
The science and effectiveness of using platelet-rich plasma derived from the patient""s own blood in surgery are documented in medical, trade and science journals. A known method for the preparation of platelets from whole blood is described in the American Association of Blood Bank""s Technical Manual, 12th Edition, 1996, at pages 700-701, Method 9.11. A system employing this method collects the patient""s whole blood into a collection unit with two integrally-attached transfer containers. The blood is collected into the collecting container, the other two transfer containers are collapsed, and the two transfer containers with the collecting container are subjected to a xe2x80x9csoft spinxe2x80x9d in a centrifuge, which brings the plasma to the top of the collecting unit, leaving red cells at the bottom. In the next step, the collecting container containing the blood is squeezed in a plasma extractor to force the platelet-rich plasma into one of the transfer containers through a connecting tube. A fraction comprising red cells remains behind in the collecting container, which is then removed. Next, the two transfer containers, the first being empty and the second containing the plasma, are subjected to a xe2x80x9cheavy spinxe2x80x9d in a centrifuge to concentrate platelets at the xe2x80x9cbottomxe2x80x9d of the second transfer container, leaving a platelet-poor fraction of the plasma (PPP) above the platelet concentrate (PC) in the second transfer container. The following step squeezes the second transfer container to express the PPP into the first transfer container. The platelet concentrate (PC) is then resuspended and collected for use. This system uses a process requiring six separate steps, including two centrifugal steps and two separation steps. The terms xe2x80x9clight spinxe2x80x9d and xe2x80x9cheavy spinxe2x80x9d are defined in Table 10.5-1 at page 716 of the AABB Technical Manual.
It is an object of this invention to provide a single use system for producing platelet concentrates (PC). Preferably, the system is in the form of a kit including disposable components supplied sterile in disposable packaging, and having all of the components required to draw blood from the patient, prevent blood coagulation, process the sample into platelet concentrate, and deliver the platelet concentrate to a surgical site. It is a particular object of the invention to provide such a system that will be useful to medical and dental practitioners, including, but not limited to, dentists, periodontists, and oral and maxillofacial surgeons.
The invention in one of its aspects provides a bag set comprising two bags joined by a tube which includes a built-in sample site at the second bag and has sloped top surface geometry at both bags for improved and more efficient cell separation and collection. This new bag set may be pre-charged with an anticoagulant. A preferred size range is 50-100 ml, but the invention is not limited to any particular size range.
In another aspect of the invention, each bag consists of two compartments, the first for the sedimentation of cellular material and the second to serve as an inflatable device for the purpose of expressing supernatant liquid from the first compartment.
In still another aspect, the invention provides a bifurcated centrifuge bucket having two wells, into each of which one of the cell bags is placed together with an inflatable device, and a means successively to inflate each inflatable device to perform each expression step following the soft spin and the heavy spin, thereby eliminating the step of removing the bag set from the bucket after each spin. In a further aspect, the invention provides means to express the supernatant liquid from within the bucket, thereby eliminating the need to remove the bag set from the bucket after the heavy spin.